Method of constructing forms for concrete structures



June 8, c. DODSON ET AL 2,680,277

METHOD OF CONSTRUCTING FORMS FOR CONCRETE STRUCTURES Filed Oct. 17, 1950 qvs lml iulll 21 J INVENTORS OMRM MGARDN R ATTORNEY Patented June 8, 1954 METHOD OF CONSTRUCTING FORMS FOR CONCRETE STRUCTURES Claude J.

Dodson. and Clarence M. Gardner,

Brevard, N. 0., assignors to E. I. du Pont de Nemours & Company, Wilmington, DeL, a corporation of Delaware Application October 17, 1950, Serial No. 190,598

- This invention relates to a clamping device, and more particularly to a brace clamp for retaining backing members in position behind concrete construction panel forms during the pouring and setting of the mix.

In the construction of concrete walls, and similar structures, it has been the practice to employ relatively large unitary panel forms, which may be, for example, 4 feet by 8 feet, or even larger. For convenience, these panels may consist of single pieces of plywood, having wood frames nailed to the back or outside surfaces thereof, together with stud pieces spaced apart along their lengths, in sufiicient number to resist distortion under the weight of the mix or from other causes. As commonly employed, the panel forms are placed one upon another with the outside frame of the upper panel resting upon the outside of the lower panel in vertical sequence, and with the edges of adjacent panels abutting. The'opposite side of the form is assembled in identical manner, after which the two sides are secured together with form ties and wedges, such as are described, for example, in U. S. Patents 2,020,912 and 1,919,751, or in other ways.

The assembled forms are finally buttressed by a succession of horizontal timbers, hereinafter referred to as wales, which may be used in pairs, each pair of wales being secured to the panels by the wedges when the wedges are assembled upon the ends of the form ties hereinbefore described. The whole form is next strengthened by disposing a number of vertical timbers, hereinafter referred to as stiffbacks, behind the wales at appropriate intervals along the full length of the form, each of the stifibacks being retained against outward movement by top and bottom bracing timbers, the outer ends of which are restrained from movement by stakes driven into the ground.

To withstand the severe stresses to which concrete construction forms are subjected, it has hitherto been the practice to nail the various form elements firmly together during erection, so that relative movement between the parts cannot occur. For this purpose, and in order to insure positive attachment, it has been the practice to apply large nails to the structural elements. Such practice results in high construction costs during both the erection stage and the dismantling stage, and also constitutes a hazard to workmen and damage to the wood form components. Furthermore, where nails are used for the joinder of-braces with stiffbacks, it is necessary to cut the upper ends of the brace members which are 1 Claim. (01. 25-131) 2 to be assembled on a bias at some angle other than the horizontal, so that these ends will abut against the stiffbacks over substantially the full area of contact.

An object of this invention is to provide an inexpensive, reliable clamp for the secure retention,

of bracing timbers against stiffbacks.

Another object of this invention is to provide a brace clamp for the retention of bracing timbers against stiffbacks which permits the'use of square-cut brace pieces and eliminates the necessity for matched fits between these elements.

Another object of this invention is to provide a brace clamp for the assembly of bracing timbers and stifibacks which may, if desired, be readily Fig. 3 is a side elevation view showing the manher in which bracing timbers are secured to stiffbacks by the clamps in the erection of panel-type construction forms.

Referring to Figures 1 and 2, one embodiment of clamp made in accordance with this invention may comprise a bolt [0 provided with two clamping discs I! and I2, respectively. Disc II is preferably fixedly attached to the head of bolt I!) by welding or in some other manner, while disc I2 is fitted loosely thereon, so that the clearance between the discs may be varied to accommodate different thicknesses of timbers therebetween. The inside surfaces of discs II and I2 are each provided with a number of barbs l3, which are preferably disposed at approximately equal intervals near the peripheries.

The clamp is provided with an operating nut I4 threadedly engaged with the end of bolt l0, nut l4 carrying integral handle bars l5 for ease in adjustment. Washer I5 is preferably interposed between nut 14 and disc 12 to minimize friction between these elements when the clamp is tightened, and the threaded end of bolt l0 may be drilled to receive cotter pin l I for the prevention of accidental disassembly of the clamp during use.

Referring to Figure 3, a typical concrete form construction may comprise panel elements -I8 having frames l9 secured to wales 20 by form ties 2| and wedges 22. The wale elements 20 may be secured to stifiback 23 by nailing, or by the use of clamps, such as those disclosed in our copending application Ser. No. 190,599, filed October 17, 1950. In usual practice, stiffbacks 23 are retained in vertical position by two or more braces 24, the lowermost brace being disposed horizontally while the others are inclined to a greater or lesser degree, depending upon the point where attachment is to be made with the stifibacks and. of course, the lengths of the bracing members.

In use, the clamps of this invention are adapted to receive the ends of braces 24 and the adjacent areas of stifi'backs 23 between discs H and I2, after which nut 14 may be drawn down to such an extent that barbs l3 penetrate into the wood and thereby secure the two members firmly together. For simplicity, it is preferred that the braces and stiiibacks be of equal thickness so that the clamp will engage each of these elements to about the same depth. However, it will be understood that the present clamp may be used with different thicknesses of brace and stiffback if the thin member of the pair is built up by nailing thereto a block of scrap lumber of appropriate thickness, so that the edges of the two members lie in approximately the same planes. Another method of clamping members of difierent thickness constitutes undercutting the thicker member 4 limited except as set forth in the following patent claim.

We claim:

The method of constructing temporary forms for concrete structures which has a vertically positioned stifiback and braces positioned in angular relation thereto and connected and retained in said positions during the pouring of concrete which comprises the steps of providing free space between the ends of the braces and the outer face of the stiifback and inserting connecting and retaining means in said free spaces with metallic discs supported on the connecting means in position to engage the opposite surfaces of the end of the braces and the opposite edges of the stiffback and forcing the discs into penetrating contact with said surfaces to secure the connecting and retaining portions in pressure-repelling position against force applied from the stifiback in the direction of the ends of the braces and force applied by the braces in the direction of the stiffback.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain Dec. 22, 1937 

